Chemical Vapor Deposition Exhaust Filter System Research And Analysis

The first and second generation semiconductor materials have made great contribution to industrial progress and social development. In recent years, the third generation new semiconductor materials such as silicon carbide(SiC), gallium nitride(GaN) develop rapidly because of their excellent properties. The preparation technologies of these new semiconductor materials have received a lot of interest. Research and development of CVD equipment which is closely related to process conditions have also attracted extensive attention. The state of gas flow is complex during reaction process, the quality and thickness uniformity of material is influenced by the control of reaction chamber internal pressure through exhaust system, and there are chemical compound with strong toxicity such as arsenic hydride and phosphorus hydride, all of these conditions put forward high demands on the equipment gas delivery system, especially exhaust system.Firstly, the applications of MOCVD equipment in LED semiconductor industry are briefly introduced, as well as the whole component system of equipment. The gas delivery system and its subsystem---exhaust system are emphatically introduced. Through the analysis of working principle of the exhaust system and schematic diagram of gas delivery system, key technologies are come up with which are disposal of exhaust gas and type selection and design of some components of exhaust system which have influence on reaction chamber internal pressure.Secondly, simulations of particle filter which is key component of exhaust system are presented. The mathematic model of filter cartridge is established on the foundation of basic CFD principle. The distribution of flow field in the filter cartridge is analyzed. The pressure drop of filter cartridge is calculated under different structure parameters of the model such as pleat number, pleat angle and pleat width. A solution to reduce the pressure drop of filter cartridge is proposed.At last, a model of shell structure of particle filter is built. The distribution of flow field in the shell structure is simulated on the basic of finite element method. By changing the shell structure during simulation, the optimal structure can be achieved which lead to less pressure drop and higher uniformity of flow distribution.